Pyronema omphalodes. Photo credit: Tom Bruns.

Pyronema omphalodes (Bull.) Fuckel is a member of the family Pyronemataceae (Ascomycota) that forms tiny pink to orangish cup-like fruiting bodies (apothecia) that are often fused together to form what looks like a pad or crust on recently burned ground. Environmental sequencing shows that Pyronema is the dominant genus in post-fire soils within a few weeks following fire, although it’s often not an abundant fruiter in such sites. It is supposed to differ from P. domesticum by its lack of sclerotia in culture, but its behavior in post-fire soils suggests that it may have some sort of resting structure in soil environments. Its rapid growth after fire is of interest because post-fire soils are rich in hydrophobic compounds, and in partially burned substrates that can last in the environment for decades and affect site productivity. This and other pyrophilous fungi are likely to affect the fate of these compounds in the soil.